Question

You need to make 10.0 L of 1.2 M KNO3. What molarity would the potassium nitrate solution need to be if you were to use only 2.5 L of it?

Answer 1

1) List the known and unknown quantities.

Final conditions

Volume 2: 10.0 L

Concentration 2: 1.2 M

Final conditions

Volume 1: 2.5 L

Concentration 1: unknown

2) Set the equation

`C1*V1=C2*V2`

3) Plug in the known values and solve for C1

`C1*(2.5\text{ }L)=(1.2\text{ }M)*(10.0\text{ }L)`
`C1=\frac{(1.2\text{ }M)*(10.0\text{ }L)}{2.5\text{ }L}=4.8\text{ }M`

The molarity would be 4.8 M.

.